DIY Shower Steamers for Colds and Congestion. These decongestant shower steamers are easy to make and a must-have for when colds, coughs, or allergies strike! Peppermint, eucalyptus and thyme essential oils combine with menthol to open sinuses and help you breathe easier. Plus, the soothing vapor can also help relieve a headache. Make these shower melts for quick natural relief. Also includes kid safe recipe.